13. Which one of the following descriptions for microelectrodes is incorrect?
(A) The dimensions of such electrodes are usually smaller than about 20 μm.
(B) The IR (current × resistance) drop of microelectrodes is higher than traditional electrodes.
(C) Such electrodes can be used for the study of chemical processes in single cells.
(D) They are also called ultramicroelectrodes or microscopic electrodes.
(E) By using such electrodes, three electrodes system is not necessary.